<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02变量与常量</title>
</head>
<body>
<script>
  var a=1;
  var b=3.14;
  var c='你们';
  var d='好呀';
  var e=true;
  console.log(a,b,c,d,e);
  console.log(typeof a,typeof b,typeof c,typeof d,typeof e);
  a=3.4;
  console.log(a,typeof a);
  a=false;
  console.log(a,typeof a);
  /*弱类型不提前绑定，存什么值就是什么类型*/
  a='HelloWorld' ;
  console.log(a,typeof a);
  let x=1;
  console.log(x,typeof x);
  /*let x=6.6;
  console.log(x,typeof x);*/
  /*let不能重复声明变量*/
  const y = 1;
  console.log(y,typeof y);
  /*y=2;*//*常量不可被修改*/

</script>
</body>
</html>